AQUEOUS PROTEIN SOLUTIONS STABLE TO DENATURATION

Aq. insulin solns. opt. contg. usual additives to adjust isotonicity, preservation and/or depot action, additionally contain a surface-active substance of formula (I) as homopolymer, block polymer or copolymer in a concn. of 2-200 mg/ml: (where R1 is H, CH3 or C2H5; n is 2-80 (pref. 8-45); and R2 and R3 are H, a 1-20C alkyl alcohol residue, a 2-20C carboxylic acid residue, a (1-10C alkyl) phenol residue or a 1-20C alkylamine residue). Inclusion of cpds. (I) in aqueous Zn-contg. solutions of bovine, porcine or human insulin or their des-B1-phenyalanine derivs. presents denaturation of the insulin that occurs on contact with hydrophobic surfaces or with air. This minimises the precipitation of denatured insulin and the occurrence of immunologically poorly tolerated denatured insulin.